The purpose of this study is to correlate serum levels of Vascular Endothelial Growth Factor (VEGF) with disease states in patients with presumed coronary artery disease. Our hypothesis is that the serum levels of VEGF will be substantially higher in patients with acute ischemic states as compared with patients without evidence for ischemia. Angiogenesis and the development of collateral blood vessels are important in patients with coronary artery disease. Most humans with occlusions of the coronary arteries have myocardial damage. However, patients who develop collateral vessels will at the time of a myocardial infarction have smaller infarcts and better heart function than patients that have no collateral vessels. The angiogenic hormone VEGF promotes collateralization and new blood vessel growth. Patients who form collaterals may produce higher levels of VEGF. Because it is not known if VEGF serum levels vary in diseased states, the aim of this pilot study is to measure VEGF levels in patients with a variety of cardiovascular disease states. Our hypothesis is that patients with unstable angina or patients recently post MI will have higher circulating levels of VEGF than patients with valvular heart disease, stable angina or non-cardiac chest pain. Patients who are undergoing cardiac catheterization will be asked to enter the study. A sample of blood will be collected from the patient and assayed for VEGF using an enzyme immune assay. The VEGF levels will be correlated with clinical data which is collected routinely by the Duke cardiovascular data bank in patients undergoing cardiac catheterization. In order to detect a 10% difference in the mean level of VEGF, using a one sided t-test with 80% power we will enroll 50 patients in each group. We have just finished enrolling these patients and will be analyzing the data in the next several months.